With the launch of the iPhone 6, 6 Plus, and Apple Watch, the tech giant is finally entering the world of contactless payments, made possible with the devices’ incorporated NFC technology.

However, following the big unveil in Cupertino on Tuesday, some commentators were questioning the level of security offered by Apple’s smartwatch when it comes to making such payments, especially given the lack of a Touch ID sensor, which the iPhone will use to authorize in-store purchases.

Well, it seems like we now have the answer. According to a Cult of Mac report, skin contact is at the heart of the Apple Watch’s security system. No, this doesn’t mean you’ll have to get up close and personal with the store assistant to perform some bizarre pre-purchase payment ritual every time you buy something. In fact, it’s all to do with keeping the Apple Watch on your wrist.

It works like this: Each time you put on your shiny new watch, you’ll be required to enter your PIN. This opens up the device for NFC payments, allowing you to use it to purchase items from stores (that support Apple Pay) as you go about your day.

The sensors on the underside of the device can detect if the watch is removed from your wrist. If this happens, you’ll have to re-enter the PIN when you put the device back on in order to re-enable its contactless payment functionality. As you can see, this should, in theory, prevent anyone other than you from using your Apple Watch to make in-store payments (unless they know your PIN, that is).

Now there will be those who are already thinking of the severed-arm scenario, but really, the chances of a criminal lopping a limb off in order to purchase a double chocolaty chip frappuccino at a nearby Starbucks seems, to put it mildly, highly unlikely. So let’s just dump that theory right now.

Although the skin-based system makes it sound as if you’ll have to enter your PIN each time you put on Apple’s new wrist-based gadget, it’s possible there’ll be an option in the watch’s settings that lets you opt out of mobile payments, thereby disabling the PIN process – much in the same way you can turn off the iPhone’s passcode.

The tech giant unveiled its first smartwatch earlier this week. The device is set to hit stores in early 2015 starting at $350.